Abstract: Flow and heat transfer model in tee junction was established and the 3D RNG k-ε turbulence model was completed to simulate the process of mixing and capture the information of velocity and temperature. The simulation results and measured data of the mean value of velocity and temperature were analyzed and compared, and are in a good agreement, which indicates that the RNG k-ε model combined with the heat transfer model can well simulate the hydraulic characteristics and heat transfer mechanism of hot and cold fluids in a tee junction. Furthermore, the upstream segment of a tee junction has two kinds: straight pipe and bend, for which the velocity and temperature distributions along different vertical lines were compared. Through the comparisons, is obtained that the hot and cold fluids are more conducive to mix when the upstream inlet section is elbow for the tee junction, which results in the temperature gradient being reduced, and the fluctuations being reduced for the beneficial security.

Key words: Tee junction, mixing, flow, heat transfer, numerical simulation